VNA Measurement for High-Speed Digital Signal Integrity

High-speed digital signals are commonplace in a variety of applications, and one of the most common carriers of digital signals is the HDMI cable. This cable contains four, 100Ω twisted pairs and a number of other signaling and power lines. Data speeds run from 4.95 GBps for 1080i video to 48 GBps for 8k video at 60 Hz or 4k video at 120 Hz frame rate for various classes of HDMI cables.An automobile is a very noisy environment for digital data, and different methods are employed to mitigate these effects. First, the data will often be recorded to maximize bit transitions to allow for successful clock recovery and to balance the running sum of 1’s and 0’s to prevent the development of a DC offset in the bit-stream. A coding method called 8B/10B is commonly used for this purpose. The serial data may also have per-emphasis added and post-processing at the receiving end might be used to improve signal integrity.